Pablo,
Visual editor many times messes up the HTML markup although I have not anyone complain about pricing table. Visual editor is one of the reasons why create shortcodes for some functions to avoid WordPress visual editor making changes to markup. We released an update to Extinct theme recently just to add a shortcode to address an issue of this type.
Will take a look at your issue and there is an update coming this week and will include the new shortcode as part of the update. For now, it’s safe to use the HTML tab if WordPress continues to messes up the layout. You can revert to an earlier revision of the page and then make the required changes. Thanks.